Rheostat for starting and controlling electric motors.



No. 785.994. PATENTED MAE. 28, 1905.

W. G. YATES. RHEOSTAT FOR STARTING AND CONTROLLING ELECTRIC MOTORS.

APPLICATION FILED SEPT. 14, 1904.

Witnesses: Inventori Wil Ham C. Yates,

iyz WW UNITED STATES Patented March 28, 1905.

PATENT OFFICE.

WILLIAM C. YATES, OF SOHENEOTADY, NEiV YORK. ASSIGNOR TO GEN- ERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

RHEOSTAT FOR STARTING AND CONTROLLING ELECTRIC MOTORS- SPECIFICATION forming part of 'Letters Patent No. 785,994, dated March 28, 1905.

Application filed September 14, 1904. Serial No. 224,378.

To all whom, it puny concern.-

panying drawing,forming a part of this speci- Beitknown tllatl,VVILLIAMC.YATES,acltification, which shows a rheostat embodying zen of the United States, residing at Schenectady, county of Schenectady, State of New 5 York, have invented certain new and useful Improvements in Rheostats for Starting and Controlling Electric Motors, of which the following is a specification.

The present invention relates to rheostats, to and more especially to that class known as motor-starting rheostats and designed for holding the electric current in check during the acceleration of a motor-armature from a state of rest to its normal running speed and 5 also for regulating the amount of current during the effective operation of the motor. The object of my invent-ion is to provide a a highlye ificient rheostat of this character which shall be of very compact and simple 0 construction and of low cost of manufacture. As rheostats have been made heretofore the stationary contacts to which the resistance member was connected have been arranged in substantially a continuous row, and the movable contact was moved thereover in a given direction, first cutting out sections of high resistance during the acceleration of the motor, and finally, while moving in the same direction, cutting out sections of resistance by which the power of the motor was controlled.

According to my invention while using the same size of resistance conductor and contacts I reduce the total dimensions of the device by arranging one half of the row of stationary contacts parallel with the other half of the row and providing two contact-arms so arranged that as one arm is moved in one direction it engages its respective row of con- 4 tacts to start the motor, and after traveling half the distance traveled by the ordinary rheostat-arm it picks up the other arm, so that by a return movement of the first arm the second is drawn forward, cutting out the resistance-sections by which the power developed by the motor is regulated.

For a more complete understanding of my invention reference may be made to the following detailed description and the accomone form of my invention.

On a stud 1 is pivoted a lever or startingarm 2, having a handle 3, by which it can be moved over a set of contacts at, connected with the coils 5 of the starting resistance. A suitable spring 6 urges the starting-arm normally toward the Zero position, where it rests on the dead-contact 7. Pivoted on the stud l is also a controlling-arm 8, on an insulated 6O portion of which is mounted theno-voltage release-magnet 9, whose keeper 10 is pivotally attached to the starting-arm 2, so that together they form an electromagnetic clutch forconnecting the two arms. ln order to 5 supply current to the magnet-coil,its terminals may slide in contact with two parallel conducting-segments 11, one connected with the field-coil 120i the motor and the other with one of the supply-mains, which is also connected with the starting-arm 2.

Parallel with the contacts 4 is a row or set of contact segments 13, connected with the coils 14: of the controlling resistance. These coils are in series with the starting resistance, the final contact at being electrically connected with the first segment 13. The controllingarm 8 has a portion 8 insulated from the rest of said arm and carrying a brush or brushes 15, bearing on said segment 13. On the por- 0 vtion 8 is a contact-clip 16, into which the starting-arm 2 can close, and thereby put the brush or brushes 15 in direct electrical connection with the supply-main. The final segment 13 is connected, as usual, with the ar 5 mature 17 of the shunt-wound motor. The arm 8 is urged toward the first segment 13 by a spring. A convenient construction is to use the same spring 6 for both arms, winding it helically around the pivot-stud 1 and let- 9 ting its ends bear, respectively, on the two arms. The result is that the arms are urged away from each other until they bring up against the stops 18 in the positions shown in the drawing.

The operation is as follows: On swinging the starting-arm over to the left it gradually cuts out the resistance-coils 5 and starts the motor. On reaching the contact 4 the starting-arm enters the clip 16, so that the current flows from the stud 1 through the arm 2 and clip directly to the insulated portion 8 of the controlling-arm and thence by the brushes 15 to the segment 13. In this position the starting-arm is magnetically clutched to the controlling-arm, since the keeper 10 has closed upon the pole-pieces of the no-voltage magnet 9, whose strength is sufficient to resist the effort of the spring to separate them. The two arms can now be moved as one back to the right, gradually cutting out the resistance-coils 1 which govern the speed of the motor. The arms will remain at any point to which they may be moved, as the spring is inoperative to move either of them so long as they are clutched together; but should the voltage fail the clutch-magnet is deenergized, and the spring instantly throws the arms apart to the positions shown, open-circuiting and stopping the motor.

It will be noted that by my invention the width of the rheostat-panel is reduced to about one-half that of one where the starting and controlling resistances are arranged in a single line, which effects an important saving in space in switchboard installations.

hat I claim as new, and desire to secure by Letters Patent of the United States, is

1. The combination with a rheostat having starting and controlling resistances arranged parallel with each other, of a starting-arm cooperating with the starting resistance, a controlling-arm cooperating with the controlling resistance, and means for connectingsaid arms when the former has cut out the starting resistance.

2. The combination with a rheostat having starting and controlling resistances arranged parallel with each other, of a starting-arm and a controlling-arm each standing normally at the beginning of the respective resistances, and means for connecting them mechanically and electrically when the starting-arm has been swung over to cut out the starting resistance.

3. The combination with a motor-starting resistance and a motor-controlling resistance, of contact-arms cooperating therewith, and a magnetic clutch for connecting said arms.

4. The combination with a motor-starting resistance and a motor-controlling resistance arranged in parallel lines and connected in series, of two contact-arms each cooperating with one of said resistances, a magnetic clutch for connecting said arms, and a spring urging them apart.

5. The combination with a motor-starting resistance and a motor-controlling resistance connected in series, of contact-arms respectresponsive to change in line-voltage, and a spring urging said arms apart.

'7. The combination with a motor-starting resistance and a motor-controlling resistance arranged in parallel lines and connected in series, of contact-arms respectively cooperating with said resistances, a clip on one arm receiving the other, an electromagnetic clutch for connecting said arms, and a spring urging them apart.

8. The combination with a motor-starting resistance and a motor-controlling resistance arranged in parallel lines and connected in series, of two contact-arms respectively cooperating with said resistances, one of said arms having an insulated contact-making portion, means for electrically connecting said portion with the other arm, and an electromagnetic clutch carried on said arms and responsive to a failure in line-voltage.

9. The combination with a motor-starting resistance and a motor-controlling resistance arranged in parallel lines and connected in series, of two contact-arms respectively cooperating with said resistances, one of said arms having an insulated contact-making portion, means for electrically connecting said portion with the other arm, an electromagnetic clutch carried on said arms and responsive to afailure in line-voltage, and two parallel conducting-segments with which the clutch-magnet terminals make sliding contact.

10. A motor starting and controlling rheostat having a contact-arm movable in one direction to start the motor, and then in a reverse direction to control the speed of said motor.

11. The combination with a motor-starting resistance and a motor-controlling resistance arranged in concentric rows and connected in series, of two contact-arms pivoted concentrically with said rows and standing normally at opposite ends thereof, a spring urging them apart, means for connecting them electrically when brought together, and a no-voltage release-magnet for clutching them together so long as there is no failure in voltage.

In witness whereof I have hereunto set my hand this 12th day of-September, 1904.

\VILLIAM U. YATES.

Witnesses:

BENJAMIN B. HULL, HELEN ORFORD.

IIS 

